Why do we use the histogram? As somebody who never took a statistics course (but had to teach a few classes on it), I wondered why is the histogram introduced in a statistics course? Usually when something is introduced in a "watered-down" way, it is important in later more advanced treatment of the course. The undergraduate course never motivates why. 
My reasoning is that, if we have a random variable, $X$, we can estimate $P(a\leq X\leq b)$ by counting how often outcomes appear in a certain interval. The smaller the interval the better. Therefore, the point of the histogram is to "piece-together" information for the distribution of $X$, which is ultimately the goal of statistics. Is this the main reason? 
 A: The histogram is an easily implemented and efficient tool to visualize the distribution of count data, say taken from a small sample, and check the adequacy of fitted models to that data.
If you would like a more advanced approach with regards to histograms, simulate a bunch of normal samples and plot it on a histogram. Now try changing the binwidths and see if you can find one that gives a good visual representation of the simulated samples. Then write a formula for an optimal binwidth based on the type and size of the data simulated.
A: Histograms, are perhaps the best-known statistical plots. If you Google images for “statistics,” you will see many histograms or histogram-like plots. Something like this:

So a down-to-earth answer to the question

why is the histogram introduced in a statistics course?

is because anyone who will be working with statistical reports of any kind is very likely to encounter histograms and he or she should know what those plots are. 
Why histograms are popular? I think there are two factors here. First, exploring the data using histograms with different numbers of bins and different cut points between bins is useful in understanding the shape of the data.  But this exploration should not be confused with manipulation of the data for presentation purposes. The latter also contributes to the popularity of histograms significantly. 
